/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.table.descriptors;

import org.apache.flink.annotation.PublicEvolving;
import org.apache.flink.api.common.typeinfo.Types;
import org.apache.flink.table.sources.tsextractors.TimestampExtractor;
import org.apache.flink.table.sources.wmstrategies.WatermarkStrategy;

import java.util.Map;

/**
 * Rowtime descriptor for describing an event time attribute in the schema.
 */
@PublicEvolving
public class Rowtime implements Descriptor {

	private final DescriptorProperties internalProperties = new DescriptorProperties(true);

	// TODO: Put these fields into RowtimeValidator once it is also ported into table-common.
	// TODO: Because these fields have polluted this API class.
	public static final String ROWTIME = "rowtime";
	public static final String ROWTIME_TIMESTAMPS_TYPE = "rowtime.timestamps.type";
	public static final String ROWTIME_TIMESTAMPS_TYPE_VALUE_FROM_FIELD = "from-field";
	public static final String ROWTIME_TIMESTAMPS_TYPE_VALUE_FROM_SOURCE = "from-source";
	public static final String ROWTIME_TIMESTAMPS_TYPE_VALUE_CUSTOM = "custom";
	public static final String ROWTIME_TIMESTAMPS_FROM = "rowtime.timestamps.from";
	public static final String ROWTIME_TIMESTAMPS_CLASS = "rowtime.timestamps.class";
	public static final String ROWTIME_TIMESTAMPS_SERIALIZED = "rowtime.timestamps.serialized";

	public static final String ROWTIME_WATERMARKS_TYPE = "rowtime.watermarks.type";
	public static final String ROWTIME_WATERMARKS_TYPE_VALUE_PERIODIC_ASCENDING = "periodic-ascending";
	public static final String ROWTIME_WATERMARKS_TYPE_VALUE_PERIODIC_BOUNDED = "periodic-bounded";
	public static final String ROWTIME_WATERMARKS_TYPE_VALUE_FROM_SOURCE = "from-source";
	public static final String ROWTIME_WATERMARKS_TYPE_VALUE_CUSTOM = "custom";
	public static final String ROWTIME_WATERMARKS_CLASS = "rowtime.watermarks.class";
	public static final String ROWTIME_WATERMARKS_SERIALIZED = "rowtime.watermarks.serialized";
	public static final String ROWTIME_WATERMARKS_DELAY = "rowtime.watermarks.delay";

	/**
	 * Sets a built-in timestamp extractor that converts an existing {@link Long} or
	 * {@link Types#SQL_TIMESTAMP} field into the rowtime attribute.
	 *
	 * @param fieldName The field to convert into a rowtime attribute.
	 */
	public Rowtime timestampsFromField(String fieldName) {
		internalProperties.putString(ROWTIME_TIMESTAMPS_TYPE, ROWTIME_TIMESTAMPS_TYPE_VALUE_FROM_FIELD);
		internalProperties.putString(ROWTIME_TIMESTAMPS_FROM, fieldName);
		return this;
	}

	/**
	 * Sets a built-in timestamp extractor that converts the assigned timestamps from
	 * a DataStream API record into the rowtime attribute and thus preserves the assigned
	 * timestamps from the source.
	 *
	 * <p>Note: This extractor only works in streaming environments.
	 */
	public Rowtime timestampsFromSource() {
		internalProperties.putString(ROWTIME_TIMESTAMPS_TYPE, ROWTIME_TIMESTAMPS_TYPE_VALUE_FROM_SOURCE);
		return this;
	}

	/**
	 * Sets a custom timestamp extractor to be used for the rowtime attribute.
	 *
	 * @param extractor The {@link TimestampExtractor} to extract the rowtime attribute
	 *                  from the physical type.
	 */
	public Rowtime timestampsFromExtractor(TimestampExtractor extractor) {
		internalProperties.putProperties(extractor.toProperties());
		return this;
	}

	/**
	 * Sets a built-in watermark strategy for ascending rowtime attributes.
	 *
	 * <p>Emits a watermark of the maximum observed timestamp so far minus 1.
	 * Rows that have a timestamp equal to the max timestamp are not late.
	 */
	public Rowtime watermarksPeriodicAscending() {
		internalProperties.putString(ROWTIME_WATERMARKS_TYPE, ROWTIME_WATERMARKS_TYPE_VALUE_PERIODIC_ASCENDING);
		return this;
	}

	/**
	 * Sets a built-in watermark strategy for rowtime attributes which are out-of-order by a bounded
	 * time interval.
	 *
	 * <p>Emits watermarks which are the maximum observed timestamp minus the specified delay.
	 *
	 * @param delay delay in milliseconds
	 */
	public Rowtime watermarksPeriodicBounded(long delay) {
		internalProperties.putString(ROWTIME_WATERMARKS_TYPE, ROWTIME_WATERMARKS_TYPE_VALUE_PERIODIC_BOUNDED);
		internalProperties.putLong(ROWTIME_WATERMARKS_DELAY, delay);
		return this;
	}

	/**
	 * Sets a built-in watermark strategy which indicates the watermarks should be preserved from
	 * the underlying DataStream API and thus preserves the assigned watermarks from the source.
	 */
	public Rowtime watermarksFromSource() {
		internalProperties.putString(ROWTIME_WATERMARKS_TYPE, ROWTIME_WATERMARKS_TYPE_VALUE_FROM_SOURCE);
		return this;
	}

	/**
	 * Sets a custom watermark strategy to be used for the rowtime attribute.
	 */
	public Rowtime watermarksFromStrategy(WatermarkStrategy strategy) {
		internalProperties.putProperties(strategy.toProperties());
		return this;
	}

	/**
	 * Converts this descriptor into a set of properties.
	 */
	@Override
	public Map<String, String> toProperties() {
		final DescriptorProperties properties = new DescriptorProperties();
		properties.putProperties(internalProperties);
		return properties.asMap();
	}
}
